projects/rgb-led-string/serial.c

   1 #include <avr/io.h>
   2 #include <util/delay.h>
   3 #include <avr/interrupt.h>
   4
   5 #include "rgbstring.h"
   6
   7 void init_serial()
   8 {
   9         PORTB &= ~(_BV(PB2) | _BV(PB1));
  10         DDRB |= _BV(PB2) | _BV(PB1);
  11
  12 #if 0
  13         TCCR0A = _BV(WGM01) | _BV(WGM00);
  14         TCCR0B = _BV(WGM02) | _BV(CS00);
  15         OCR0A = 2;
  16 #endif
  17
  18         zero_frame();
  19 }
  20
  21 static void send_byte(unsigned char b)
  22 {
  23         unsigned char i, mask;
  24
  25 #if 0
  26         USIDR = b;
  27         USISR = _BV(USIOIF);
  28         USICR = _BV(USIWM0) | _BV(USICS0);
  29
  30         while (!(USISR & _BV(USIOIF)))
  31                 ;
  32 #endif
  33
  34 #if 1
  35         USIDR = b;
  36         USISR = _BV(USIOIF);
  37
  38         while ( (USISR & _BV(USIOIF)) == 0 ) {
  39                 USICR = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK);
  40                 USICR = _BV(USIWM0) | _BV(USICS1) | _BV(USICLK) | _BV(USITC);
  41         }
  42 #endif
  43
  44 #if 0
  45         for (i = 0; i < 8; i++) {
  46                 USICR = _BV(USIWM0) | _BV(USITC);
  47                 USICR = _BV(USIWM0) | _BV(USITC) | _BV(USICLK);
  48         }
  49 #endif
  50
  51 #if 0
  52         for (i = 0; i < 8; i++) {
  53                 PORTB &= ~_BV(PB2);             // clock low
  54                 if (b & 0x80)                   // data bit on or off
  55                         PORTB |= _BV(PB1);
  56                 else
  57                         PORTB &= ~_BV(PB1);
  58                 b <<= 1;
  59                 PORTB |= _BV(PB2);              // clock high
  60         }
  61 #endif
  62 }
  63
  64 void end_frame()
  65 {
  66         PORTB &= ~_BV(PB2);                     // clock low
  67         _delay_us(1000);
  68 }
  69
  70 void send_rgb(unsigned char r, unsigned char g, unsigned char b)
  71 {
  72         send_byte(r);
  73         send_byte(g);
  74         send_byte(b);
  75 }
  76
  77
  78 void zero_frame()
  79 {
  80         unsigned char i;
  81
  82         for (i = 0; i < STRIP_SIZE; i++) {
  83                 send_rgb(0, 0, 0);
  84         }
  85
  86         end_frame();
  87 }
  88